31-01-2019, 11:12 PM
What is history? Has it been subject to extreme rpm? Has it been dropped on end, cracking the nitride layer? Perhaps before delivery.
Has it been reground, removing the nitride layer?
I presume the nitriding is the main reason for Phoenix reliability but the process is not majic. Stresses go up with the square of revs and 10% stress increase has a huge effect on fatigue life.
It is odd that cranks fail at th rear where bridge bending is supposedly least. I guess the flywheel acts as a rigid anchor. Torque is reckoned not very significant.
Has it been reground, removing the nitride layer?
I presume the nitriding is the main reason for Phoenix reliability but the process is not majic. Stresses go up with the square of revs and 10% stress increase has a huge effect on fatigue life.
It is odd that cranks fail at th rear where bridge bending is supposedly least. I guess the flywheel acts as a rigid anchor. Torque is reckoned not very significant.